Couple likely did nothing. Many times in a case where perp commits violent act before taking a child, it's also done to scare/shock the child into submission. For example, you murder Jayme's parents in front of her which will numb her senses and put her into a state of shock. Makes it easier to take her. You also instill an element of fear because you just demonstrated you're willing to brutally kill two innocent people so you give the victim the impression that it happened to them and it will happen to you unless you do exactly what I say.
Brian Mitchell used the same tactic on Elizabeth Smart only he didn't actually kill her parents. He told her that if she screamed or made a sound or ever tried to escape, he would go back and murder her whole family. Children are often easier victims for the reason that it's easier to create a mental prison around them to gain compliance by threatening things they hold dear. For all we know, perp could be threatening Jayme further because she has other relatives that are still living.